Polymeric resinous material derived from limonene, dicyclopentadiene and tertiary-butyl styrene

ABSTRACT

The present application relates to polymeric resinous material comprising 
     (1) from 15 to 39 weight percent units derived from limonene; 
     (2) from 15 to 39 weight percent units derived from dicyclopentadiene; and 
     (3) from 46 to 70 weight percent units derived from tertiary-butyl styrene; 
     wherein the sum of the weight percent units derived from limonene and dicyclopentadiene range from 30 to 54 weight percent units of the resin.

This is a Divisional of application Ser. No. 09/251,282, filed on Feb.16, 1999, presently U.S. Pat. No. 6,221,990.

BACKGROUND OF THE INVENTION

Polymeric resins have been used in treads of tires to improve traction.Unfortunately, one consequence of their use is a decrease in durabilityand treadwear.

Polymeric resinous materials containing units derived from piperylene,units derived from 2-methyl-2-butene and units derived fromdicyclopentadiene are commercially available from The Goodyear Tire &Rubber Company under the designation WINGTACK® 115. These polymericresinous materials find use in adhesives.

SUMMARY OF THE INVENTION

The present invention relates to a polymeric resinous material derivedfrom limonene, dicyclopentadiene and tert-butyl styrene.

DEAILED DESCRIPTION OF THE INVENTION

There is disclosed a polymeric resinous material comprising

(a) from 15 to 39 weight percent units derived from limonene;

(b) from 15 to 39 weight percent units derived from dicyclopentadiene;and

(c) from 46 to 70 weight percent units derived from tertiary-butylstyrene;

wherein the sum of the weight percent units derived from limonene anddicyclopentadiene range from 30 to 54 weight percent units of the resin.

In addition, there is disclosed a rubber composition comprising (a) adiene-based elastomer containing olefinic unsaturation and (b) 1 to 80phr of a polymeric resinous material comprising

(1) from 15 to 39 weight percent units derived from limonene;

(2) from 15 to 39 weight percent units derived from dicyclopentadiene;and

(3) from 46 to 70 weight percent units derived from tertiary-butylstyrene;

wherein the sum of the weight percent units derived from limonene anddicyclopentadiene range from 30 to 54 weight percent units of the resin.

In addition, there is disclosed a pneumatic tire having a treadcomprised of (a) a diene-based elastomer containing olefinicunsaturation and (b) 1 to 80 phr of a polymeric resinous materialcomprising

(1) from 15 to 39 weight percent units derived from limonene;

(2) from 15 to 39 weight percent units derived from dicyclopentadiene;and

(3) from 46 to 70 weight percent units derived from tertiary-butylstyrene;

wherein the sum of the weight percent units derived from limonene anddicyclopentadiene range from 30 to 54 weight percent units of the resin.

The polymeric resinous material for use in the present inventioncomprises from about 15 to about 39 weight percent units derived fromlimonene; from about 15 to about 39 weight percent units derived fromdicyclopentadiene; and 46 to 70 weight percent units derived fromtertiary-butyl styrene. Preferably, the resin comprises from about 22 toabout 27 weight percent units derived from limonene; from about 22 toabout 27 weight percent units derived from dicyclopentadiene; and from46 to 56 weight percent units derived from tertiary-butyl styrene.

In a particularly preferred embodiment, the weight ratio of unitsderived from limonene:dicyclopentadiene:tertiary-butyl styrene is 1:1:2.

The polymeric resin is particularly suited for use in a diene-basedelastomer in an amount ranging from about 1 to 80 phr (parts by weightper 100 parts by weight of rubber). Preferably, the polymeric resin ispresent in an amount ranging from 10 to 40 phr.

The resins may be prepared using various anhydrous metallic halidecatalysts. Representative examples of such catalysts are fluorides,chlorides and bromides, of aluminum, tin and boron. Such catalystsinclude, for example, aluminum chloride, stannic chloride and borontrifluoride. Alkyl aluminum dihalides are also suitable, representativeexamples of which are methyl aluminum dichloride, ethyl aluminumdichloride and isopropyl aluminum dichloride.

In carrying out the polymerization reaction, the hydrocarbon mixture isbrought into contact with the anhydrous halide catalyst. Generally, thecatalyst is used in particulate form having a particle size in the rangeof from about 5 to about 200 mesh size, although larger or smallerparticles can be used. The amount of catalyst used is not criticalalthough sufficient catalyst must be used to cause a polymerizationreaction to occur. The catalyst may be added to the olefinic hydrocarbonmixture or the hydrocarbon mixture may be added to the catalyst. Ifdesired, the catalyst and mixture of hydrocarbons can be addedsimultaneously or intermittently to a reactor. The reaction can beconducted continuously or by batch process techniques generally known tothose skilled in the art.

The reaction is conveniently carried out in the presence of a diluentbecause it is usually exothermic. Various diluents which are inert inthat they do not enter into the polymerization reaction may be used.Representative examples of inert diluents are aliphatic hydrocarbonssuch as pentane, hexane, cyclohexane and heptane, aromatic hydrocarbonssuch as toluene, xylene and benzene, and unreacted residual hydrocarbonsfrom the reaction.

A wide range of temperatures can be used for the polymerizationreaction. The polymerization can be carried out at temperatures in therange of from about −20° C. to about 100° C., although usually thereaction is carried out at a temperature in the range of from about 0°C. to about 50° C. The polymerization reaction pressure is not criticaland may be atmospheric or above or below atmospheric pressure.Generally, a satisfactory polymerization can be conducted when thereaction is carried out at about autogenous pressure developed by thereactor under the operating conditions used. The time of the reaction isnot generally critical and reaction times can vary from a few seconds to12 hours or more.

Upon completion of the reaction the hydrocarbon mixture is neutralizedfollowed by isolation of the resin solution. The resin solution issteam-distilled with the resulting resin being allowed to cool.

The resins can optionally be modified by the addition of up to about 25weight percent of other unsaturated hydrocarbons and particularlyhydrocarbons containing from 9 to 10 carbon atoms and mixtures thereof.Representative examples of such hydrocarbons are 3-methyl styrene,4-methyl styrene, 1-methyl indene, 2-methyl indene, 3-methyl indene andmixtures thereof.

The resinous materials of this invention are characterized by having aGardner color of from about 2 to about 10, a capillary tube meltingpoint of from about 100° C. to about 200° C., good heat stability and aspecific gravity of from about 0.85 to about 1.0. They typically have acapillary tube melting point of 100° C. to 200° C. after steam-strippingto remove lower molecular weight compounds; although, when prepared inthe presence of a chlorinated hydrocarbon solvent, their softening pointis increased within that range. These resins are generally soluble inaliphatic hydrocarbons such as pentane, hexane, heptane and aromatichydrocarbons such as benzene and toluene.

The tread of the tire of the present invention contains an elastomercontaining olefinic unsaturation. The phrase “rubber or elastomercontaining olefinic unsaturation” is intended to include both naturalrubber and its various raw and reclaim forms as well as varioussynthetic rubbers. In the description of this invention, the terms“rubber” and “elastomer” may be used interchangeably, unless otherwiseprescribed. The terms “rubber composition,” “compounded rubber” and“rubber compound” are used interchangeably to refer to rubber which hasbeen blended or mixed with various ingredients and materials and suchterms are well known to those having skill in the rubber mixing orrubber compounding art. Representative synthetic polymers are thehomopolymerization products of butadiene and its homologues andderivatives, for example, methylbutadiene, dimethylbutadiene andpentadiene as well as copolymers such as those formed from butadiene orits homologues or derivatives with other unsaturated monomers. Among thelatter are acetylenes, for example, vinyl acetylene; olefins, forexample, isobutylene, which copolymerizes with isoprene to form butylrubber; vinyl compounds, for example, acrylic acid, acrylonitrile (whichpolymerize with butadiene to form NBR), methacrylic acid and styrene,the latter compound polymerizing with butadiene to form SBR, as well asvinyl esters and various unsaturated aldehydes, ketones and ethers,e.g., acrolein, methyl isopropenyl ketone and vinylethyl ether. Specificexamples of synthetic rubbers include neoprene (polychloroprene),polybutadiene (including cis-1,4-polybutadiene), polyisoprene (includingcis-1,4-polyisoprene), butyl rubber, styrene/isoprene/butadiene rubber,copolymers of 1,3-butadiene or isoprene with monomers such as styrene,acrylonitrile and methyl methacrylate, as well as ethylene/propyleneterpolymers, also known as ethylene/propylene/diene monomer (EPDM) and,in particular, ethylene/propylene/dicyclopentadiene terpolymers. Thepreferred rubber or elastomers are polybutadiene and SBR.

In one aspect, the rubber is preferably of at least two of diene-basedrubbers. For example, a combination of two or more rubbers is preferredsuch as cis 1,4-polyisoprene rubber (natural or synthetic, althoughnatural is preferred), 3,4-polyisoprene rubber,styrene/isoprene/butadiene rubber, emulsion and solution polymerizationderived styrene/butadiene rubbers, cis 1,4-polybutadiene rubbers andemulsion polymerization prepared butadiene/acrylonitrile copolymers.

In one aspect of this invention, an emulsion polymerization derivedstyrene/butadiene (E-SBR) might be used having a relatively conventionalstyrene content of about 20 to about 28 weight percent bound styrene or,for some applications, an E-SBR having a medium to relatively high boundstyrene content; namely, a bound styrene content of about 30 to about 45percent. The relatively high styrene content of about 30 to about 45 forthe E-SBR can be considered beneficial for a purpose of enhancingtraction, or skid resistance, of the tire tread. The presence of theE-SBR itself is considered beneficial for a purpose of enhancingprocessability of the uncured elastomer composition mixture, especiallyin comparison to a utilization of a solution polymerization prepared SBR(S-SBR).

By emulsion polymerization prepared E-SBR, it is meant that styrene and1,3-butadiene are copolymerized as an aqueous emulsion. Such are wellknown to those skilled in such art. The bound styrene content can vary,for example, from about 5 to about 50 percent. In one aspect, the E-SBRmay also contain acrylonitrile to form a terpolymer rubber, as E-SBAR,in amounts, for example, of about 2 to about 30 weight percent boundacrylonitrile in the terpolymer.

Emulsion polymerization prepared styrene/butadiene/acrylonitrileterpolymer rubbers containing about 2 to about 40 weight percent boundacrylonitrile in the terpolymer are also contemplated as diene-basedrubbers for use in this invention.

The solution polymerization prepared SBR (S-SBR) typically has a boundstyrene content in a range of about 5 to about 50, preferably about 9 toabout 36, percent. The S-SBR can be conveniently prepared, for example,by organo lithium catalyzation in the presence of an organic hydrocarbonsolvent.

A purpose of using S-SBR is for improved tire rolling resistance as aresult of lower hysteresis when it is used in a tire tread composition.

The 3,4-polyisoprene rubber (3,4-PI) is considered beneficial for apurpose of enhancing the tire's traction when it is used in a tire treadcomposition. The 3,4-PI and use thereof is more fully described in U.S.Pat. No. 5,087,668 which is incorporated herein by reference. The Tgrefers to the glass transition temperature which can conveniently bedetermined by a differential scanning calorimeter at a heating rate of10° C. per minute.

The cis 1,4-polybutadiene rubber (BR) is considered to be beneficial fora purpose of enhancing the tire tread's wear, or treadwear. Such BR canbe prepared, for example, by organic solution polymerization of1,3-butadiene. The BR may be conveniently characterized, for example, byhaving at least a 90 percent cis 1,4-content.

The cis 1,4-polyisoprene (synthetic) and cis 1,4-polyisoprene naturalrubber are well known to those having skill in the rubber art.

The term “phr” as used herein, and according to conventional practice,refers to “parts by weight of a respective material per 100 parts byweight of rubber, or elastomer.”

In one embodiment, the rubber composition in the tread contains asufficient amount of filler to contribute a reasonably high modulus andhigh resistance to tear. The filler may be added in amounts ranging from5 to 250 phr. When the filler is silica, the silica is generally presentin an amount ranging from 10 to 80 phr. Preferably, the silica ispresent in an amount ranging from 15 to 70 phr. When the filler iscarbon black, the amount of carbon black will vary from 0 to 150 phr.Preferably, the amount of carbon black will range from 10 to 130 phr.

The commonly employed particulate precipitated silica used in rubbercompounding applications can be used as the silica in this invention.These precipitated silicas include, for example, those obtained by theacidification of a soluble silicate; e.g., sodium silicate.

Such silicas might be characterized, for example, by having a BETsurface area, as measured using nitrogen gas, preferably in the range ofabout 40 to about 600, and more usually in a range of about 50 to about300 square meters per gram. The BET method of measuring surface area isdescribed in the Journal of the American Chemical Society, Volume 60,page 304 (1930).

The silica may also be typically characterized by having adibutylphthalate (DBP) absorption value in a range of about 100 to about400, and more usually about 150 to about 300.

The silica might be expected to have an average ultimate particle size,for example, in the range of 0.01 to 0.05 micron as determined by theelectron microscope, although the silica particles may be even smaller,or possibly larger, in size.

Various commercially available silicas may be considered for use in thisinvention such as, only for example herein, and without limitation,silicas commercially available from PPG Industries under the Hi-Siltrademark with designations 210, 243, etc; silicas available fromRhone-Poulenc, with, for example, designations of Z1165MP and Z165GR andsilicas available from Degussa AG with, for example, designations VN2and VN3, etc.

The processing of the sulfur vulcanizable rubber may be conducted in thepresence of a sulfur containing organosilicon compound. Examples ofsuitable sulfur containing organosilicon compounds are of the formula:

Z-Alk-S_(n)-Alk-Z  (I)

in which Z is selected from the group consisting of

where R¹ is an alkyl group of 1 to 4 carbon atoms, cyclohexyl or phenyl;

R² is alkoxy of 1 to 8 carbon atoms, or cycloalkoxy of 5 to 8 carbonatoms;

Alk is a divalent hydrocarbon of 1 to 18 carbon atoms and n is aninteger of 2 to 8.

Specific examples of sulfur containing organosilicon compounds which maybe used in accordance with the present invention include:3,3′-bis(trimethoxysilylpropyl) disulfide,3,3′-bis(triethoxysilylpropyl) tetrasulfide,3,3′-bis(triethoxysilylpropyl) octasulfide,3,3′-bis(trimethoxysilylpropyl) tetrasulfide,2,2′-bis(triethoxysilylethyl) tetrasulfide,3,3′-bis(trimethoxysilylpropyl) trisulfide,3,3′-bis(triethoxysilylpropyl) trisulfide,3,3′-bis(tributoxysilylpropyl) disulfide,3,3′-bis(trimethoxysilylpropyl) hexasulfide,3,3′-bis(trimethoxysilylpropyl) octasulfide,3,3′-bis(trioctoxysilylpropyl) tetrasulfide,3,3′-bis(trihexoxysilylpropyl) disulfide,3,3′-bis(tri-2″-ethylhexoxysilylpropyl) trisulfide,3,3′-bis(triisooctoxysilylpropyl) tetrasulfide,3,3′-bis(tri-t-butoxysilylpropyl) disulfide, 2,2′-bis(methoxy diethoxysilyl ethyl) tetrasulfide, 2,2′-bis(tripropoxysilylethyl) pentasulfide,3,3′-bis(tricyclohexoxysilylpropyl) tetrasulfide,3,3′-bis(tricyclopentoxysilylpropyl) trisulfide,2,2′-bis(tri-2″-methylcyclohexoxysilylethyl) tetrasulfide,bis(trimethoxysilylmethyl) tetrasulfide, 3-methoxy ethoxy propoxysilyl3′-diethoxybutoxysilylpropyltetrasulfide, 2,2′-bis(dimethylmethoxysilylethyl) disulfide, 2,2′-bis(dimethyl sec.butoxysilylethyl)trisulfide, 3,3′-bis(methyl butylethoxysilylpropyl) tetrasulfide,3,3′-bis(di t-butylmethoxysilylpropyl) tetrasulfide, 2,2′-bis(phenylmethyl methoxysilylethyl) trisulfide, 3,3′-bis(diphenylisopropoxysilylpropyl) tetrasulfide, 3,3′-bis(diphenylcyclohexoxysilylpropyl) disulfide, 3,3′-bis(dimethylethylmercaptosilylpropyl) tetrasulfide, 2,2′-bis(methyldimethoxysilylethyl) trisulfide, 2,2′-bis(methylethoxypropoxysilylethyl) tetrasulfide, 3,3′-bis(diethylmethoxysilylpropyl) tetrasulfide, 3,3′-bis(ethyl di-sec.butoxysilylpropyl) disulfide, 3,3′-bis(propyl diethoxysilylpropyl)disulfide, 3,3′-bis(butyl dimethoxysilylpropyl) trisulfide,3,3′-bis(phenyl dimethoxysilylpropyl) tetrasulfide, 3-phenylethoxybutoxysilyl 3′-trimethoxysilylpropyl tetrasulfide,4,4′-bis(trimethoxysilylbutyl) tetrasulfide,6,6′-bis(triethoxysilylhexyl) tetrasulfide,12,12′-bis(triisopropoxysilyl dodecyl) disulfide,18,18′-bis(trimethoxysilyloctadecyl) tetrasulfide,18,18′-bis(tripropoxysilyloctadecenyl) tetrasulfide,4,4′-bis(trimethoxysilyl-buten-2-yl) tetrasulfide,4,4′-bis(trimethoxysilylcyclohexylene) tetrasulfide,5,5′-bis(dimethoxymethylsilylpentyl) trisulfide,3,3′-bis(trimethoxysilyl-2-methylpropyl) tetrasulfide,3,3′-bis(dimethoxyphenylsilyl-2-methylpropyl) disulfide.

The preferred sulfur containing organosilicon compounds are the3,3′-bis(trimethoxy or triethoxy silylpropyl) sulfides. The mostpreferred compound is 3,3′-bis(triethoxysilylpropyl) tetrasulfide.Therefore, as to Formula I, preferably Z is

where R² is an alkoxy of 2 to 4 carbon atoms, with 2 carbon atoms beingparticularly preferred; Alk is a divalent hydrocarbon of 2 to 4 carbonatoms, with 3 carbon atoms being particularly preferred; and n is aninteger of from 3 to 5, with 4 being particularly preferred.

The amount of the sulfur containing organosilicon compound of Formula Iin a rubber composition will vary depending on the level of silica thatis used. Generally speaking, the amount of the compound of formula II,if used, will range from 0.01 to 1.0 parts by weight per part by weightof the silica. Preferably, the amount will range from 0.05 to 0.4 partsby weight per part by weight of the silica.

The rubber compositions of the present invention may contain a methylenedonor and a methylene acceptor. The term “methylene donor” is intendedto mean a compound capable of reacting with a methylene acceptor (suchas resorcinol or its equivalent containing a present hydroxyl group) andgenerate the resin in-situ. Examples of methylene donors which aresuitable for use in the present invention includehexamethylenetetramine, hexaethoxymethylmelamine,hexamethoxymethylmelamine, lauryloxymethylpyridinium chloride,ethoxymethylpyridinium chloride, trioxan hexamethoxymethylmelamine, thehydroxy groups of which may be esterified or partly esterified, andpolymers of formaldehyde such as paraformaldehyde. In addition, themethylene donors may be N-substituted oxymethylmelamines, of the generalformula:

wherein X is an alkyl having from 1 to 8 carbon atoms, R³, R⁴, R⁵, R⁶and R⁷ are individually selected from the group consisting of hydrogen,an alkyl having from 1 to 8 carbon atoms and the group —CH₂OX. Specificmethylene donors include hexakis-(methoxymethyl)melamine,N,N′,N″-trimethyl/N,N′,N″-trimethylolmelamine, hexamethylolmelamine,N,N′,N″-dimethylolmelamine, N-methylolmelamine, N,N′-dimethylolmelamine,N,N′,N″-tris(methoxymethyl)melamine andN,N′N″-tributyl-N,N′,N″-trimethylol-melamine. The N-methylol derivativesof melamine are prepared by known methods.

The amount of methylene donor and methylene acceptor that is present inthe rubber stock may vary. Typically, the amount of methylene donor andmethylene acceptor that are present will range from about 0.1 phr to10.0 phr. Preferably, the amount of methylene donor and methyleneacceptor ranges from about 2.0 phr to 5.0 phr for each.

The weight ratio of methylene donor to the methylene acceptor may vary.Generally speaking, the weight ratio will range from about 1:10 to about10:1. Preferably, the weight ratio ranges from about 1:3 to 3:1.

It is readily understood by those having skill in the art that therubber composition would be compounded by methods generally known in therubber compounding art, such as mixing the various sulfur-vulcanizableconstituent rubbers with various commonly used additive materials. Asknown to those skilled in the art, depending on the intended use of thesulfur vulcanizable and sulfur-vulcanized material (rubbers), theadditives mentioned below are selected and commonly used in conventionalamounts. Representative examples of sulfur donors include elementalsulfur (free sulfur), an amine disulfide, polymeric polysulfide andsulfur olefin adducts. Preferably, the sulfur vulcanizing agent iselemental sulfur. The sulfur vulcanizing agent may be used in an amountranging from 0.5 to 8 phr, with a range of from 1.5 to 6 phr beingpreferred. Typical amounts of processing oils comprise about 1 to about50 phr. Such processing aids can include, for example, aromatic,naphthenic and/or paraffinic processing oils. Typical amounts ofantioxidants comprise about 1 to about 5 phr. Representativeantioxidants may be, for example, diphenyl-p-phenylenediamine andothers, such as, for example, those disclosed in the Vanderbilt RubberHandbook (1978), pages 344-346. Typical amounts of antiozonants compriseabout 1 to 5 phr. Typical amounts of fatty acids, if used, which caninclude stearic acid comprise about 0.5 to about 3 phr. Typical amountsof zinc oxide comprise about 2 to about 5 phr. Typical amounts ofmicrocrystalline and paraffinic waxes comprise about 1 to about 10 phr.Often microcrystalline waxes are used. Typical amounts of peptizerscomprise about 0.1 to about 1 phr. Typical peptizers may be, forexample, pentachlorothiophenol and dibenzamidodiphenyl disulfide.

Accelerators are used to control the time and/or temperature requiredfor vulcanization and to improve the properties of the vulcanizate. Inone embodiment, a single accelerator system may be used; i.e., primaryaccelerator. The primary accelerator(s) may be used in total amountsranging from about 0.5 to about 4, preferably about 0.8 to about 1.5,phr. In another embodiment, combinations of a primary and a secondaryaccelerator might be used with the secondary accelerator being used insmaller amounts, such as from about 0.05 to about 3 phr, in order toactivate and to improve the properties of the vulcanizate. Combinationsof these accelerators might be expected to produce a synergistic effecton the final properties and are somewhat better than those produced byuse of either accelerator alone. In addition, delayed actionaccelerators may be used which are not affected by normal processingtemperatures but produce a satisfactory cure at ordinary vulcanizationtemperatures. Vulcanization retarders might also be used. Suitable typesof accelerators that may be used in the present invention are amines,disulfides, guanidines, thioureas, thiazoles, thiurams, sulfenamides,dithiocarbamates and xanthates. Preferably, the primary accelerator is asulfenamide. If a second accelerator is used, the secondary acceleratoris preferably a guanidine, dithiocarbamate or thiuram compound.

The mixing of the rubber composition can be accomplished by methodsknown to those having skill in the rubber mixing art. For example, theingredients are typically mixed in at least two stages; namely, at leastone non-productive stage followed by a productive mix stage. The finalcuratives including sulfur vulcanizing agents are typically mixed in thefinal stage which is conventionally called the “productive” mix stage inwhich the mixing typically occurs at a temperature, or ultimatetemperature, lower than the mix temperature(s) than the precedingnon-productive mix stage(s). The rubber and polymeric resin are mixed inone or more non-productive mix stages. The terms “non-productive” and“productive” mix stages are well known to those having skill in therubber mixing art.

Vulcanization of the pneumatic tire of the present invention isgenerally carried out at conventional temperatures ranging from about100° C. to 200° C. Preferably, the vulcanization is conducted attemperatures ranging from about 110° C. to 180° C. Any of the usualvulcanization processes may be used such as heating in a press or mold,heating with superheated steam or hot air or in a salt bath.

The following examples are presented in order to illustrate but notlimit the present invention.

Cure properties were determined using a Monsanto oscillating discrheometer which was operated at a temperature of 150° C. and at afrequency of 11 hertz. A description of oscillating disc rheometers canbe found in the Vanderbilt Rubber Handbook edited by Robert O. Ohm(Norwalk, Conn., R. T. Vanderbilt Company, Inc., 1990), pages 554-557.The use of this cure meter and standardized values read from the curveare specified in ASTM D-2084. A typical cure curve obtained on anoscillating disc rheometer is shown on page 555 of the 1990 edition ofthe Vanderbilt Rubber Handbook.

In such an oscillating disc rheometer, compounded rubber samples aresubjected to an oscillating shearing action of constant amplitude. Thetorque of the oscillating disc embedded in the stock that is beingtested that is required to oscillate the rotor at the vulcanizationtemperature is measured. The values obtained using this cure test arevery significant since changes in the rubber or the compounding recipeare very readily detected. It is obvious that it is normallyadvantageous to have a fast cure rate.

In the following examples, the Flexsys Rubber Process Analyzer (RPA)2000 was used to determine dynamic mechanical Theological properties.The curing conditions were 160° C., 1.667 Hz, 15.8 minutes and 0.7percent strain. A description of the RPA 2000, its capability, samplepreparation, tests and subtests can be found in these references. H APawlowski and J S Dick, Rubber World, June 1992; J S Dick and H APawlowski, Rubber World, January 1997; and J S Dick and J A Pawlowski,Rubber & Plastics News, Apr. 26 and May 10, 1993.

The compounded rubber sample is placed on the bottom die. When the diesare brought together, the sample is in a pressurized cavity where itwill be subjected to a sinusoidal oscillating shearing action of thebottom die. A torque transducer connected to the upper die measures theamount of torque transmitted through the sample as a result of theoscillations. Torque is translated into the shear modulus, G, bycorrecting for the die form factor and the strain. The RPA 2000 iscapable of testing uncured or cured rubber with a high degree ofrepeatability and reproducibility. The tests and subtests availableinclude frequency sweeps at constant temperature and strain, curing atconstant temperature and frequency, strain sweeps at constanttemperature and frequency and temperature sweeps at constant strain andfrequency. The accuracy and precision of the instrument allowsreproducible detection of changes in the compounded sample.

The values reported for the storage modulus, (G′), loss compliance (J″)and tan delta are obtained from a strain sweep at 100° C. and 1 Hzfollowing the cure test. These properties represent the viscoelasticresponse of a test sample to shear deformation at a constant temperatureand frequency.

EXAMPLE 1

Three hundred parts of cyclohexane and 50 parts of anhydrous aluminumchloride were placed into a reactor. While continuously stirring themixture, 600 parts of a hydrocarbon mixture was slowly added to thereactor over a period of about 60 minutes. The hydrocarbon mixtureconsisted of 30 percent inert hydrocarbons with the remaining 70 percentby weight of the mixture comprising the following resin forming

Component Percent Limonene 25.0 Dicyclopentadiene 25.0 t-Butyl Styrene50.0

The temperature of the reaction was maintained in a range of about 25°to 30° C. After an hour of agitation from the time of final addition,the hydrocarbon mixture was added to approximately 4,000 parts of a 25percent solution of isopropyl alcohol in water to neutralize anddecompose the aluminum chloride. The aqueous layer was removed and theresin solution washed with an additional 4,000 parts of thealcohol/water blend.

The resulting resin solution was steam-distilled at a pot temperature ofabout 235° C. The resulting residual molten resin was poured from thepot onto an aluminum tray and cooled to room temperature to form 400parts of a hard brittle pale yellow resin having a capillary tubemelting point of 120 to 156° C. Small molecule GPC analysis gives amolecular weight distribution of 8.4 percent in the 11,000 MW range,84.7 percent in the 2400 MW range, 2.4 percent in the 520 MW range and3.3 percent in the 400 MW range.

EXAMPLE 2

In this example, various resins were evaluated in a rubber compound.

Rubber compositions containing the materials set out in Tables 1 and 2were prepared in a BR Banbury™ mixer using two separate stages ofaddition (mixing); namely, one non-productive mix stage and oneproductive mix stage. The non-productive stage was mixed for 3.5 minutesor to a rubber temperature of 160° C., whichever occurred first. Themixing time for the productive stage was to a rubber temperature of 108°C.

The rubber compositions are identified herein as Samples 1-3. Samples 1and 2 are considered herein as controls without the use of the resinused in the present invention being added to the rubber composition.Samples 1 and 2 each contain commercially available resins.

The samples were cured at about 150° C. for about 28 minutes.

Table 2 illustrates the behavior and physical properties of the curedSamples 1-3.

Lab data reveals that the new DCPD/Limonene/Tertiary Butyl Styrene resinenhances the dry traction and durability properties simultaneously.Generally, increasing a compound's durability reduces its dry traction.Comparing the dynamic properties (RPA 2000) and stress-strain data (ATS)of the Coumarone-Indene (Sample 2) and phenolic resins (Sample 1), thetypical tradeoff of sacrificing durability (lower G′ at 40 percentstrain, 300 percent modulus and tensile strength) for improved drytraction (increased tan delta and loss compliance at 40 percent strain)is demonstrated. Sample 1 (phenolic resin) is a soft compound with highhysteresis. Sample 2 (Coumarone-Indene resin) is a stiff compound withlow hysteresis.

The DCPD/Limonene/Tertiary Butyl Styrene resin versus Sample 1 showsthat the durability is significantly improved (G′ at 40 percent strain,300 percent modulus and tensile strength) and dry traction is improved(tan delta and J″ at 40 percent). The DCPD/Limonene/Tertiary ButylStyrene resin versus the Sample 2 shows that the durability is onlyslightly reduced (G′ at 40 percent strain, 300 percent modulus andtensile strength) and the dry traction is significantly improved (tandelta and J″ at 40 percent). The DCPD/Limonene/Tertiary Butyl Styreneresin shows the best tradeoff between durability and dry traction.

TABLE 1 Control Control Samples 1 2 3 Non-Productive Solution SBR¹ 100100 100 Carbon Black² 88 88 88 Aromatic Oil 50 50 50 Stearic Acid 0.960.96 0.96 Zinc Oxide 1.20 1.20 1.20 Antioxidant³ 0.67 0.67 0.67 PhenolicResin⁴ 21.5 0 0 Coumarone Indene⁵ Resin 0 21.5 0 Resin of Example 1 0 021.5 Productive Accelerators⁶ 2.4 2.4 2.4 Accelerator⁷ 0.20 0.20 0.20Sulfur 1.22 1.22 1.22 ¹Solution SBR containing 32% styrene a Tg of −17°C. and a base Mooney of 88 when oil extended (20 phr oil) the Mooney was45. The solution SBR was obtained from the Goodyear Tire & RubberCompany. ²I₂ = 122 and DBP = 114 ³Polymerized1,2-dihydro-2,2,4-tremethylquinoline ⁴Unreactive phenol-formaldehyderesin having a softening point of 106-114° C. (Ring and Ball) which iscommercially available from Schenectady Chemical under the designationCRJ-418. ⁵Coumarone Indene Resin having a softening point of 100° C.which is commercially available from Neville Chemical under thedesignature Cumar ™ R-13. ⁶N-cyclohexyl benzothiazole-2-sulfenamide⁷Tetramethyl thiuram disulfide

TABLE 2 Sample 1 2 3 Phenolic resin 21.5 0 0 Coumarone Indene Resin 021.5 0 Resin of Ex. 1 0 0 21.5 Rheometer 150° C. T25 (min) 8.25 12.3 7.1T90 (min) 18.3 17.05 23.95 Min Torque 6.97 7.43 9.04 Max Torque (36′)18.07 22.82 22.51 Delta Torque 11.1 15.39 13.47 Final Torque (60′) 18.1722.97 22.65 RPA 2000 G′ 40% (KPa) 386 456 428 Tan Delta 40% 0.253 0.2560.315 J″ 40% 1/MPa 0.61 0.53 0.067 ATS, cure 28 minutes @ 150° C. 300%Modulus, MPa 3.51 5.13 4.96 Break Strength, MPa 8.50 10.30 9.52Elongation, % 627 572 576 Rebound RT 8.2 8.2 8.6 Rebound 100° C. 28.932.0 31.8

While certain representative embodiments and details have been shown forthe purpose of illustrating the invention, it will be apparent to thoseskilled in this art that various changes and modifications may be madetherein without departing from the spirit or scope of the invention.

What is claimed is:
 1. A polymeric resinous material comprising (a) from15 to 39 weight percent units derived from limonene; (b) from 15 to 39weight percent units derived from dicyclopentadiene; and (c) from 46 to70 weight percent units derived from tertiary-butyl styrene; wherein thesum of the weight percent units derived from limonene anddicyclopentadiene range from 30 to 54 weight percent units of the resin.2. The polymeric resinous material according to claim 1 having acapillary tube melting point of from about 100° C. to about 200° C. 3.The polymeric resinous material according to claim 1 comprising (1) from22 to 27 weight percent units derived from limonene; (2) from 22 to 27weight percent units derived from dicyclopentadiene; and (3) from 46 to56 weight percent units derived from tertiary-butyl styrene.
 4. Thepolymeric resinous material according to claim 3 wherein the weightratio of limonene:dicyclopentadiene:tertiary-butyl styrene is 1:1:2. 5.The polymeric resinous material according to claim 1 wherein thepolymeric resinous material is modified by containing up to about 25weight percent units derived from other unsaturated hydrocarbonscontaining from 9 to 10 carbon atoms.
 6. The polymeric resinous materialaccording to claim 1 wherein said polymeric resinous material isprepared by the method which comprises polymerizing a mixture oflimonene, dicyclopentadiene and tertiary-butyl styrene in the presenceof an anhydrous halide catalyst selected from the fluorides, chloridesand bromides of aluminum, tin and boron and from alkyl aluminumdihalides selected from methyl aluminum dichloride, ethyl aluminumdichloride and isopropyl aluminum dichloride.
 7. The polymeric resinousmaterial according to claim 6 wherein the halide catalysts are selectedfrom aluminum chloride, stannic chloride, boron trifluoride, methylaluminum dichloride, ethyl aluminum dichloride and isopropyl aluminumdichloride.
 8. A rubber composition comprising (a) a diene-basedelastomer containing olefinic unsaturation and (b) 1 to 80 phr of apolymeric resinous material comprising (1) from 15 to 39 weight percentunits derived from limonene; (2) from 15 to 39 weight percent unitsderived from dicyclopentadiene; and (3) from 46 to 70 weight percentunits derived from tertiary-butyl styrene; wherein the sum of the weightpercent units derived from limonene and dicyclopentadiene-range from 30to 54 weight percent units of the resin.
 9. The rubber compositionaccording to claim 8 characterized by the polymeric resinous materialhaving a capillary tube melting point of from about 100° C. to about200° C.
 10. The rubber composition according to claim 8 wherein from 20to 40 phr of a polymeric resinous material is present.
 11. The rubbercomposition according to claim 8 wherein said polymeric resinousmaterial comprises (1) from 22 to 27 weight percent units derived fromlimonene; (2) from 22 to 27 weight percent units derived fromdicyclopentadiene; and (3) from 46 to 56 weight percent units derivedfrom tertiary-butyl styrene.
 12. The rubber composition according toclaim 11 wherein the weight ratio oflimonene:dicyclopentadiene:tertiary-butyl styrene is 1:1:2.
 13. Therubber composition according to claim 8 wherein the polymeric resinousmaterial is modified by containing up to about 25 weight percent unitsderived from other unsaturated hydrocarbons containing from 9 to 10carbon atoms.
 14. The rubber composition according to claim 8 whereinsaid polymeric resinous material is prepared by the method whichcomprises polymerizing a mixture of limonene, dicyclopentadiene andtertiary-butyl styrene in the presence of an anhydrous halide catalystselected from the fluorides, chlorides and bromides of aluminum, tin andboron and from alkyl aluminum dihalides selected from methyl aluminumdichloride, ethyl aluminum dichloride and isopropyl aluminum dichloride.15. The rubber composition according to claim 14 wherein the halidecatalysts are selected from aluminum chloride, stannic chloride, borontrifluoride, methyl aluminum dichloride, ethyl aluminum dichloride andisopropyl aluminum dichloride.
 16. The rubber composition according toclaim 8 wherein said elastomer containing olefinic unsaturation isselected from the group consisting of natural rubber, neoprene,polyisoprene, polybutadiene, styrene-butadiene copolymer,styrene/isoprene/butadiene rubber, methyl methacrylate-butadienecopolymer, isoprene-styrene copolymer, methyl methacrylate-isoprenecopolymer, acrylonitrile-isoprene copolymer, acrylonitrile-butadienecopolymer, EPDM and mixtures thereof.
 17. The rubber compositionaccording to claim 16 wherein said elastomer is styrene-butadienecopolymer.
 18. The rubber composition according to claim 17 wherein saidstyrene-butadiene copolymer has a bound styrene content of from 20 to 45percent.
 19. The rubber composition according to claim 8 wherein afiller is present in said elastomer in an amount ranging from 10 to 250phr.